| Message ID | 1398879850-9111-4-git-send-email-dianders@chromium.org (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
On Wed, 30 Apr 2014, Doug Anderson wrote: > The cros_ec_spi transfer had two problems with its timeout code: > > 1. It looked at the timeout even in the case that it found valid data. > 2. If the cros_ec_spi code got switched out for a while, it's possible > it could get a timeout after a single loop. Let's be paranoid and > make sure we do one last transfer after the timeout expires. > > Signed-off-by: Doug Anderson <dianders@chromium.org> > Acked-by: Lee Jones <lee.jones@linaro.org> > Reviewed-by: Simon Glass <sjg@chromium.org> > Tested-by: Andrew Bresticker <abrestic@chromium.org> > Tested-by: Stephen Warren <swarren@nvidia.com> > --- > Changes in v3: None > Changes in v2: None > > drivers/mfd/cros_ec_spi.c | 15 ++++++++++++--- > 1 file changed, 12 insertions(+), 3 deletions(-) Applied, thanks. > diff --git a/drivers/mfd/cros_ec_spi.c b/drivers/mfd/cros_ec_spi.c > index a2a605d..4f863c3 100644 > --- a/drivers/mfd/cros_ec_spi.c > +++ b/drivers/mfd/cros_ec_spi.c > @@ -113,7 +113,9 @@ static int cros_ec_spi_receive_response(struct cros_ec_device *ec_dev, > > /* Receive data until we see the header byte */ > deadline = jiffies + msecs_to_jiffies(EC_MSG_DEADLINE_MS); > - do { > + while (true) { > + unsigned long start_jiffies = jiffies; > + > memset(&trans, 0, sizeof(trans)); > trans.cs_change = 1; > trans.rx_buf = ptr = ec_dev->din; > @@ -134,12 +136,19 @@ static int cros_ec_spi_receive_response(struct cros_ec_device *ec_dev, > break; > } > } > + if (ptr != end) > + break; > > - if (time_after(jiffies, deadline)) { > + /* > + * Use the time at the start of the loop as a timeout. This > + * gives us one last shot at getting the transfer and is useful > + * in case we got context switched out for a while. > + */ > + if (time_after(start_jiffies, deadline)) { > dev_warn(ec_dev->dev, "EC failed to respond in time\n"); > return -ETIMEDOUT; > } > - } while (ptr == end); > + } > > /* > * ptr now points to the header byte. Copy any valid data to the
diff --git a/drivers/mfd/cros_ec_spi.c b/drivers/mfd/cros_ec_spi.c index a2a605d..4f863c3 100644 --- a/drivers/mfd/cros_ec_spi.c +++ b/drivers/mfd/cros_ec_spi.c @@ -113,7 +113,9 @@ static int cros_ec_spi_receive_response(struct cros_ec_device *ec_dev, /* Receive data until we see the header byte */ deadline = jiffies + msecs_to_jiffies(EC_MSG_DEADLINE_MS); - do { + while (true) { + unsigned long start_jiffies = jiffies; + memset(&trans, 0, sizeof(trans)); trans.cs_change = 1; trans.rx_buf = ptr = ec_dev->din; @@ -134,12 +136,19 @@ static int cros_ec_spi_receive_response(struct cros_ec_device *ec_dev, break; } } + if (ptr != end) + break; - if (time_after(jiffies, deadline)) { + /* + * Use the time at the start of the loop as a timeout. This + * gives us one last shot at getting the transfer and is useful + * in case we got context switched out for a while. + */ + if (time_after(start_jiffies, deadline)) { dev_warn(ec_dev->dev, "EC failed to respond in time\n"); return -ETIMEDOUT; } - } while (ptr == end); + } /* * ptr now points to the header byte. Copy any valid data to the